This application is for continued core support of the Mental Retardation Research Center in the B. F. Stolinsky Research Laboratories at the University of Colorado Health Sciences Center. The Stolinsky Laboratories and the Mental Retardation Research Center were opened in 1968, and now houses six principal investigators whose research impacts substantially on mental retardation and developmental disabilities. Most of the research being carried out in this center is on inherited causes of central nervous system dysfunction, with a primary focus on inborn errors of mitochondrial function, although substantial effort is also focussed on environmental causes, including nutritional deficiency and viral infection, and at how these conditions impact on cognitive development. Studies on inherited metabolic causes of central nervous system dysfunction focus on glutaric acidemia types I and II, glycerol kinase deficiency, and disorders of the mitochondrial respiratory chain, the primary aim of these studies being to better understand pathogenesis, so that efforts to treat can have a more logical basis. Studies of environmental causes of mental retardation and developmental disability examine the impact of anoxia, zinc deficiency in infancy and during gestation, and latent viral infections in the newborn period on subsequent cognition. Additional studies are aimed at defining the precise nature of central nervous system involvement in various inborn errors and in the recombinant 8 syndrome, a newly described cytogenetic abnormality. Core facilities for which support is sought include administration, cell biology (including tissue culture, molecular biology, and cytogenetics), animal care, mass spectrometry, developmental neuropsychology, and glassware washing services.